Revert "Add Basilisk"

This reverts commit e72ef92b5bdc43cd2584198e2e54e951b70299e8.

1 files changed, 0 insertions, 863 deletions

diff --git a/application/basilisk/modules/WindowsPreviewPerTab.jsm b/application/basilisk/modules/WindowsPreviewPerTab.jsm
deleted file mode 100644
index f033b529c..000000000
--- a/application/basilisk/modules/WindowsPreviewPerTab.jsm
+++ /dev/null
@@ -1,863 +0,0 @@
-/* vim: se cin sw=2 ts=2 et filetype=javascript :
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-/*
- * This module implements the front end behavior for AeroPeek. Starting in
- * Windows Vista, the taskbar began showing live thumbnail previews of windows
- * when the user hovered over the window icon in the taskbar. Starting with
- * Windows 7, the taskbar allows an application to expose its tabbed interface
- * in the taskbar by showing thumbnail previews rather than the default window
- * preview. Additionally, when a user hovers over a thumbnail (tab or window),
- * they are shown a live preview of the window (or tab + its containing window).
- *
- * In Windows 7, a title, icon, close button and optional toolbar are shown for
- * each preview. This feature does not make use of the toolbar. For window
- * previews, the title is the window title and the icon the window icon. For
- * tab previews, the title is the page title and the page's favicon. In both
- * cases, the close button "does the right thing."
- *
- * The primary objects behind this feature are nsITaskbarTabPreview and
- * nsITaskbarPreviewController. Each preview has a controller. The controller
- * responds to the user's interactions on the taskbar and provides the required
- * data to the preview for determining the size of the tab and thumbnail. The
- * PreviewController class implements this interface. The preview will request
- * the controller to provide a thumbnail or preview when the user interacts with
- * the taskbar. To reduce the overhead of drawing the tab area, the controller
- * implementation caches the tab's contents in a <canvas> element. If no
- * previews or thumbnails have been requested for some time, the controller will
- * discard its cached tab contents.
- *
- * Screen real estate is limited so when there are too many thumbnails to fit
- * on the screen, the taskbar stops displaying thumbnails and instead displays
- * just the title, icon and close button in a similar fashion to previous
- * versions of the taskbar. If there are still too many previews to fit on the
- * screen, the taskbar resorts to a scroll up and scroll down button pair to let
- * the user scroll through the list of tabs. Since this is undoubtedly
- * inconvenient for users with many tabs, the AeroPeek objects turns off all of
- * the tab previews. This tells the taskbar to revert to one preview per window.
- * If the number of tabs falls below this magic threshold, the preview-per-tab
- * behavior returns. There is no reliable way to determine when the scroll
- * buttons appear on the taskbar, so a magic pref-controlled number determines
- * when this threshold has been crossed.
- */
-this.EXPORTED_SYMBOLS = ["AeroPeek"];
-
-const Cc = Components.classes;
-const Ci = Components.interfaces;
-const Cu = Components.utils;
-
-Cu.import("resource://gre/modules/NetUtil.jsm");
-Cu.import("resource://gre/modules/PlacesUtils.jsm");
-Cu.import("resource://gre/modules/PrivateBrowsingUtils.jsm");
-Cu.import("resource://gre/modules/Services.jsm");
-Cu.import("resource://gre/modules/XPCOMUtils.jsm");
-
-// Pref to enable/disable preview-per-tab
-const TOGGLE_PREF_NAME = "browser.taskbar.previews.enable";
-// Pref to determine the magic auto-disable threshold
-const DISABLE_THRESHOLD_PREF_NAME = "browser.taskbar.previews.max";
-// Pref to control the time in seconds that tab contents live in the cache
-const CACHE_EXPIRATION_TIME_PREF_NAME = "browser.taskbar.previews.cachetime";
-
-const WINTASKBAR_CONTRACTID = "@mozilla.org/windows-taskbar;1";
-
-// Various utility properties
-XPCOMUtils.defineLazyServiceGetter(this, "imgTools",
-                                   "@mozilla.org/image/tools;1",
-                                   "imgITools");
-XPCOMUtils.defineLazyModuleGetter(this, "PageThumbs",
-                                  "resource://gre/modules/PageThumbs.jsm");
-
-// nsIURI -> imgIContainer
-function _imageFromURI(uri, privateMode, callback) {
-  let channel = NetUtil.newChannel({
-    uri,
-    loadUsingSystemPrincipal: true,
-    contentPolicyType: Ci.nsIContentPolicy.TYPE_INTERNAL_IMAGE
-  });
-
-  try {
-    channel.QueryInterface(Ci.nsIPrivateBrowsingChannel);
-    channel.setPrivate(privateMode);
-  } catch (e) {
-    // Ignore channels which do not support nsIPrivateBrowsingChannel
-  }
-  NetUtil.asyncFetch(channel, function(inputStream, resultCode) {
-    if (!Components.isSuccessCode(resultCode))
-      return;
-    try {
-      let out_img = { value: null };
-      imgTools.decodeImageData(inputStream, channel.contentType, out_img);
-      callback(out_img.value);
-    } catch (e) {
-      // We failed, so use the default favicon (only if this wasn't the default
-      // favicon).
-      let defaultURI = PlacesUtils.favicons.defaultFavicon;
-      if (!defaultURI.equals(uri))
-        _imageFromURI(defaultURI, privateMode, callback);
-    }
-  });
-}
-
-// string? -> imgIContainer
-function getFaviconAsImage(iconurl, privateMode, callback) {
-  if (iconurl) {
-    _imageFromURI(NetUtil.newURI(iconurl), privateMode, callback);
-  } else {
-    _imageFromURI(PlacesUtils.favicons.defaultFavicon, privateMode, callback);
-  }
-}
-
-// Snaps the given rectangle to be pixel-aligned at the given scale
-function snapRectAtScale(r, scale) {
-  let x = Math.floor(r.x * scale);
-  let y = Math.floor(r.y * scale);
-  let width = Math.ceil((r.x + r.width) * scale) - x;
-  let height = Math.ceil((r.y + r.height) * scale) - y;
-
-  r.x = x / scale;
-  r.y = y / scale;
-  r.width = width / scale;
-  r.height = height / scale;
-}
-
-// PreviewController
-
-/*
- * This class manages the behavior of thumbnails and previews. It has the following
- * responsibilities:
- * 1) responding to requests from Windows taskbar for a thumbnail or window
- *    preview.
- * 2) listens for dom events that result in a thumbnail or window preview needing
- *    to be refresh, and communicates this to the taskbar.
- * 3) Handles querying and returning to the taskbar new thumbnail or window
- *    preview images through PageThumbs.
- *
- * @param win
- *        The TabWindow (see below) that owns the preview that this controls
- * @param tab
- *        The <tab> that this preview is associated with
- */
-function PreviewController(win, tab) {
-  this.win = win;
-  this.tab = tab;
-  this.linkedBrowser = tab.linkedBrowser;
-  this.preview = this.win.createTabPreview(this);
-
-  this.tab.addEventListener("TabAttrModified", this);
-
-  XPCOMUtils.defineLazyGetter(this, "canvasPreview", function() {
-    let canvas = PageThumbs.createCanvas();
-    canvas.mozOpaque = true;
-    return canvas;
-  });
-}
-
-PreviewController.prototype = {
-  QueryInterface: XPCOMUtils.generateQI([Ci.nsITaskbarPreviewController,
-                                         Ci.nsIDOMEventListener]),
-
-  destroy() {
-    this.tab.removeEventListener("TabAttrModified", this);
-
-    // Break cycles, otherwise we end up leaking the window with everything
-    // attached to it.
-    delete this.win;
-    delete this.preview;
-  },
-
-  get wrappedJSObject() {
-    return this;
-  },
-
-  // Resizes the canvasPreview to 0x0, essentially freeing its memory.
-  resetCanvasPreview() {
-    this.canvasPreview.width = 0;
-    this.canvasPreview.height = 0;
-  },
-
-  /**
-   * Set the canvas dimensions.
-   */
-  resizeCanvasPreview(aRequestedWidth, aRequestedHeight) {
-    this.canvasPreview.width = aRequestedWidth;
-    this.canvasPreview.height = aRequestedHeight;
-  },
-
-
-  get zoom() {
-    // Note that winutils.fullZoom accounts for "quantization" of the zoom factor
-    // from nsIContentViewer due to conversion through appUnits.
-    // We do -not- want screenPixelsPerCSSPixel here, because that would -also-
-    // incorporate any scaling that is applied due to hi-dpi resolution options.
-    return this.tab.linkedBrowser.fullZoom;
-  },
-
-  get screenPixelsPerCSSPixel() {
-    let chromeWin = this.tab.ownerGlobal;
-    let windowUtils = chromeWin.getInterface(Ci.nsIDOMWindowUtils);
-    return windowUtils.screenPixelsPerCSSPixel;
-  },
-
-  get browserDims() {
-    return this.tab.linkedBrowser.getBoundingClientRect();
-  },
-
-  cacheBrowserDims() {
-    let dims = this.browserDims;
-    this._cachedWidth = dims.width;
-    this._cachedHeight = dims.height;
-  },
-
-  testCacheBrowserDims() {
-    let dims = this.browserDims;
-    return this._cachedWidth == dims.width &&
-      this._cachedHeight == dims.height;
-  },
-
-  /**
-   * Capture a new thumbnail image for this preview. Called by the controller
-   * in response to a request for a new thumbnail image.
-   */
-  updateCanvasPreview(aFullScale, aCallback) {
-    // Update our cached browser dims so that delayed resize
-    // events don't trigger another invalidation if this tab becomes active.
-    this.cacheBrowserDims();
-    PageThumbs.captureToCanvas(this.linkedBrowser, this.canvasPreview,
-                               aCallback, { fullScale: aFullScale });
-    // If we're updating the canvas, then we're in the middle of a peek so
-    // don't discard the cache of previews.
-    AeroPeek.resetCacheTimer();
-  },
-
-  updateTitleAndTooltip() {
-    let title = this.win.tabbrowser.getWindowTitleForBrowser(this.linkedBrowser);
-    this.preview.title = title;
-    this.preview.tooltip = title;
-  },
-
-  // nsITaskbarPreviewController
-
-  // window width and height, not browser
-  get width() {
-    return this.win.width;
-  },
-
-  // window width and height, not browser
-  get height() {
-    return this.win.height;
-  },
-
-  get thumbnailAspectRatio() {
-    let browserDims = this.browserDims;
-    // Avoid returning 0
-    let tabWidth = browserDims.width || 1;
-    // Avoid divide by 0
-    let tabHeight = browserDims.height || 1;
-    return tabWidth / tabHeight;
-  },
-
-  /**
-   * Responds to taskbar requests for window previews. Returns the results asynchronously
-   * through updateCanvasPreview.
-   *
-   * @param aTaskbarCallback nsITaskbarPreviewCallback results callback
-   */
-  requestPreview(aTaskbarCallback) {
-    // Grab a high res content preview
-    this.resetCanvasPreview();
-    this.updateCanvasPreview(true, (aPreviewCanvas) => {
-      let winWidth = this.win.width;
-      let winHeight = this.win.height;
-
-      let composite = PageThumbs.createCanvas();
-
-      // Use transparency, Aero glass is drawn black without it.
-      composite.mozOpaque = false;
-
-      let ctx = composite.getContext("2d");
-      let scale = this.screenPixelsPerCSSPixel / this.zoom;
-
-      composite.width = winWidth * scale;
-      composite.height = winHeight * scale;
-
-      ctx.save();
-      ctx.scale(scale, scale);
-
-      // Draw chrome. Note we currently do not get scrollbars for remote frames
-      // in the image above.
-      ctx.drawWindow(this.win.win, 0, 0, winWidth, winHeight, "rgba(0,0,0,0)");
-
-      // Draw the content are into the composite canvas at the right location.
-      ctx.drawImage(aPreviewCanvas, this.browserDims.x, this.browserDims.y,
-                    aPreviewCanvas.width, aPreviewCanvas.height);
-      ctx.restore();
-
-      // Deliver the resulting composite canvas to Windows
-      this.win.tabbrowser.previewTab(this.tab, function() {
-        aTaskbarCallback.done(composite, false);
-      });
-    });
-  },
-
-  /**
-   * Responds to taskbar requests for tab thumbnails. Returns the results asynchronously
-   * through updateCanvasPreview.
-   *
-   * Note Windows requests a specific width and height here, if the resulting thumbnail
-   * does not match these dimensions thumbnail display will fail.
-   *
-   * @param aTaskbarCallback nsITaskbarPreviewCallback results callback
-   * @param aRequestedWidth width of the requested thumbnail
-   * @param aRequestedHeight height of the requested thumbnail
-   */
-  requestThumbnail(aTaskbarCallback, aRequestedWidth, aRequestedHeight) {
-    this.resizeCanvasPreview(aRequestedWidth, aRequestedHeight);
-    this.updateCanvasPreview(false, (aThumbnailCanvas) => {
-      aTaskbarCallback.done(aThumbnailCanvas, false);
-    });
-  },
-
-  // Event handling
-
-  onClose() {
-    this.win.tabbrowser.removeTab(this.tab);
-  },
-
-  onActivate() {
-    this.win.tabbrowser.selectedTab = this.tab;
-
-    // Accept activation - this will restore the browser window
-    // if it's minimized
-    return true;
-  },
-
-  // nsIDOMEventListener
-  handleEvent(evt) {
-    switch (evt.type) {
-      case "TabAttrModified":
-        this.updateTitleAndTooltip();
-        break;
-    }
-  }
-};
-
-XPCOMUtils.defineLazyGetter(PreviewController.prototype, "canvasPreviewFlags",
-  function() {
- let canvasInterface = Ci.nsIDOMCanvasRenderingContext2D;
-                return canvasInterface.DRAWWINDOW_DRAW_VIEW
-                     | canvasInterface.DRAWWINDOW_DRAW_CARET
-                     | canvasInterface.DRAWWINDOW_ASYNC_DECODE_IMAGES
-                     | canvasInterface.DRAWWINDOW_DO_NOT_FLUSH;
-});
-
-// TabWindow
-
-/*
- * This class monitors a browser window for changes to its tabs
- *
- * @param win
- *        The nsIDOMWindow browser window
- */
-function TabWindow(win) {
-  this.win = win;
-  this.tabbrowser = win.gBrowser;
-
-  this.previews = new Map();
-
-  for (let i = 0; i < this.tabEvents.length; i++)
-    this.tabbrowser.tabContainer.addEventListener(this.tabEvents[i], this);
-
-  for (let i = 0; i < this.winEvents.length; i++)
-    this.win.addEventListener(this.winEvents[i], this);
-
-  this.tabbrowser.addTabsProgressListener(this);
-
-  AeroPeek.windows.push(this);
-  let tabs = this.tabbrowser.tabs;
-  for (let i = 0; i < tabs.length; i++)
-    this.newTab(tabs[i]);
-
-  this.updateTabOrdering();
-  AeroPeek.checkPreviewCount();
-}
-
-TabWindow.prototype = {
-  _enabled: false,
-  _cachedWidth: 0,
-  _cachedHeight: 0,
-  tabEvents: ["TabOpen", "TabClose", "TabSelect", "TabMove"],
-  winEvents: ["resize"],
-
-  destroy() {
-    this._destroying = true;
-
-    let tabs = this.tabbrowser.tabs;
-
-    this.tabbrowser.removeTabsProgressListener(this);
-
-    for (let i = 0; i < this.winEvents.length; i++)
-      this.win.removeEventListener(this.winEvents[i], this);
-
-    for (let i = 0; i < this.tabEvents.length; i++)
-      this.tabbrowser.tabContainer.removeEventListener(this.tabEvents[i], this);
-
-    for (let i = 0; i < tabs.length; i++)
-      this.removeTab(tabs[i]);
-
-    let idx = AeroPeek.windows.indexOf(this.win.gTaskbarTabGroup);
-    AeroPeek.windows.splice(idx, 1);
-    AeroPeek.checkPreviewCount();
-  },
-
-  get width() {
-    return this.win.innerWidth;
-  },
-  get height() {
-    return this.win.innerHeight;
-  },
-
-  cacheDims() {
-    this._cachedWidth = this.width;
-    this._cachedHeight = this.height;
-  },
-
-  testCacheDims() {
-    return this._cachedWidth == this.width && this._cachedHeight == this.height;
-  },
-
-  // Invoked when the given tab is added to this window
-  newTab(tab) {
-    let controller = new PreviewController(this, tab);
-    // It's OK to add the preview now while the favicon still loads.
-    this.previews.set(tab, controller.preview);
-    AeroPeek.addPreview(controller.preview);
-    // updateTitleAndTooltip relies on having controller.preview which is lazily resolved.
-    // Now that we've updated this.previews, it will resolve successfully.
-    controller.updateTitleAndTooltip();
-  },
-
-  createTabPreview(controller) {
-    let docShell = this.win
-                  .QueryInterface(Ci.nsIInterfaceRequestor)
-                  .getInterface(Ci.nsIWebNavigation)
-                  .QueryInterface(Ci.nsIDocShell);
-    let preview = AeroPeek.taskbar.createTaskbarTabPreview(docShell, controller);
-    preview.visible = AeroPeek.enabled;
-    preview.active = this.tabbrowser.selectedTab == controller.tab;
-    this.onLinkIconAvailable(controller.tab.linkedBrowser,
-                             controller.tab.getAttribute("image"));
-    return preview;
-  },
-
-  // Invoked when the given tab is closed
-  removeTab(tab) {
-    let preview = this.previewFromTab(tab);
-    preview.active = false;
-    preview.visible = false;
-    preview.move(null);
-    preview.controller.wrappedJSObject.destroy();
-
-    this.previews.delete(tab);
-    AeroPeek.removePreview(preview);
-  },
-
-  get enabled() {
-    return this._enabled;
-  },
-
-  set enabled(enable) {
-    this._enabled = enable;
-    // Because making a tab visible requires that the tab it is next to be
-    // visible, it is far simpler to unset the 'next' tab and recreate them all
-    // at once.
-    for (let [, preview] of this.previews) {
-      preview.move(null);
-      preview.visible = enable;
-    }
-    this.updateTabOrdering();
-  },
-
-  previewFromTab(tab) {
-    return this.previews.get(tab);
-  },
-
-  updateTabOrdering() {
-    let previews = this.previews;
-    let tabs = this.tabbrowser.tabs;
-
-    // Previews are internally stored using a map, so we need to iterate the
-    // tabbrowser's array of tabs to retrieve previews in the same order.
-    let inorder = [];
-    for (let t of tabs) {
-      if (previews.has(t)) {
-        inorder.push(previews.get(t));
-      }
-    }
-
-    // Since the internal taskbar array has not yet been updated we must force
-    // on it the sorting order of our local array.  To do so we must walk
-    // the local array backwards, otherwise we would send move requests in the
-    // wrong order.  See bug 522610 for details.
-    for (let i = inorder.length - 1; i >= 0; i--) {
-      inorder[i].move(inorder[i + 1] || null);
-    }
-  },
-
-  // nsIDOMEventListener
-  handleEvent(evt) {
-    let tab = evt.originalTarget;
-    switch (evt.type) {
-      case "TabOpen":
-        this.newTab(tab);
-        this.updateTabOrdering();
-        break;
-      case "TabClose":
-        this.removeTab(tab);
-        this.updateTabOrdering();
-        break;
-      case "TabSelect":
-        this.previewFromTab(tab).active = true;
-        break;
-      case "TabMove":
-        this.updateTabOrdering();
-        break;
-      case "resize":
-        if (!AeroPeek._prefenabled)
-          return;
-        this.onResize();
-        break;
-    }
-  },
-
-  // Set or reset a timer that will invalidate visible thumbnails soon.
-  setInvalidationTimer() {
-    if (!this.invalidateTimer) {
-      this.invalidateTimer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
-    }
-    this.invalidateTimer.cancel();
-
-    // delay 1 second before invalidating
-    this.invalidateTimer.initWithCallback(() => {
-      // invalidate every preview. note the internal implementation of
-      // invalidate ignores thumbnails that aren't visible.
-      this.previews.forEach(function(aPreview) {
-        let controller = aPreview.controller.wrappedJSObject;
-        if (!controller.testCacheBrowserDims()) {
-          controller.cacheBrowserDims();
-          aPreview.invalidate();
-        }
-      });
-    }, 1000, Ci.nsITimer.TYPE_ONE_SHOT);
-  },
-
-  onResize() {
-    // Specific to a window.
-
-    // Call invalidate on each tab thumbnail so that Windows will request an
-    // updated image. However don't do this repeatedly across multiple resize
-    // events triggered during window border drags.
-
-    if (this.testCacheDims()) {
-      return;
-    }
-
-    // update the window dims on our TabWindow object.
-    this.cacheDims();
-
-    // invalidate soon
-    this.setInvalidationTimer();
-  },
-
-  invalidateTabPreview(aBrowser) {
-    for (let [tab, preview] of this.previews) {
-      if (aBrowser == tab.linkedBrowser) {
-        preview.invalidate();
-        break;
-      }
-    }
-  },
-
-  // Browser progress listener
-
-  onLocationChange(aBrowser) {
-    // I'm not sure we need this, onStateChange does a really good job
-    // of picking up page changes.
-    // this.invalidateTabPreview(aBrowser);
-  },
-
-  onStateChange(aBrowser, aWebProgress, aRequest, aStateFlags, aStatus) {
-    if (aStateFlags & Ci.nsIWebProgressListener.STATE_STOP &&
-        aStateFlags & Ci.nsIWebProgressListener.STATE_IS_NETWORK) {
-      this.invalidateTabPreview(aBrowser);
-    }
-  },
-
-  directRequestProtocols: new Set([
-    "file", "chrome", "resource", "about"
-  ]),
-  onLinkIconAvailable(aBrowser, aIconURL) {
-    let requestURL = null;
-    if (aIconURL) {
-      let shouldRequestFaviconURL = true;
-      try {
-        let urlObject = NetUtil.newURI(aIconURL);
-        shouldRequestFaviconURL =
-          !this.directRequestProtocols.has(urlObject.scheme);
-      } catch (ex) {}
-
-      requestURL = shouldRequestFaviconURL ?
-        "moz-anno:favicon:" + aIconURL :
-        aIconURL;
-    }
-    let isDefaultFavicon = !requestURL;
-    getFaviconAsImage(
-      requestURL,
-      PrivateBrowsingUtils.isWindowPrivate(this.win),
-      img => {
-        let index = this.tabbrowser.browsers.indexOf(aBrowser);
-        // Only add it if we've found the index and the URI is still the same.
-        // The tab could have closed, and there's no guarantee the icons
-        // will have finished fetching 'in order'.
-        if (index != -1) {
-          let tab = this.tabbrowser.tabs[index];
-          let preview = this.previews.get(tab);
-          if (tab.getAttribute("image") == aIconURL ||
-              (!preview.icon && isDefaultFavicon)) {
-            preview.icon = img;
-          }
-        }
-      }
-    );
-  }
-}
-
-// AeroPeek
-
-/*
- * This object acts as global storage and external interface for this feature.
- * It maintains the values of the prefs.
- */
-this.AeroPeek = {
-  available: false,
-  // Does the pref say we're enabled?
-  __prefenabled: false,
-
-  _enabled: true,
-
-  initialized: false,
-
-  // nsITaskbarTabPreview array
-  previews: [],
-
-  // TabWindow array
-  windows: [],
-
-  // nsIWinTaskbar service
-  taskbar: null,
-
-  // Maximum number of previews
-  maxpreviews: 20,
-
-  // Length of time in seconds that previews are cached
-  cacheLifespan: 20,
-
-  initialize() {
-    if (!(WINTASKBAR_CONTRACTID in Cc))
-      return;
-    this.taskbar = Cc[WINTASKBAR_CONTRACTID].getService(Ci.nsIWinTaskbar);
-    this.available = this.taskbar.available;
-    if (!this.available)
-      return;
-
-    this.prefs.addObserver(TOGGLE_PREF_NAME, this, true);
-    this.enabled = this._prefenabled = this.prefs.getBoolPref(TOGGLE_PREF_NAME);
-    this.initialized = true;
-  },
-
-  destroy: function destroy() {
-    this._enabled = false;
-
-    if (this.cacheTimer)
-      this.cacheTimer.cancel();
-  },
-
-  get enabled() {
-    return this._enabled;
-  },
-
-  set enabled(enable) {
-    if (this._enabled == enable)
-      return;
-
-    this._enabled = enable;
-
-    this.windows.forEach(function(win) {
-      win.enabled = enable;
-    });
-  },
-
-  get _prefenabled() {
-    return this.__prefenabled;
-  },
-
-  set _prefenabled(enable) {
-    if (enable == this.__prefenabled) {
-      return;
-    }
-    this.__prefenabled = enable;
-
-    if (enable) {
-      this.enable();
-    } else {
-      this.disable();
-    }
-  },
-
-  _observersAdded: false,
-
-  enable() {
-    if (!this._observersAdded) {
-      this.prefs.addObserver(DISABLE_THRESHOLD_PREF_NAME, this, true);
-      this.prefs.addObserver(CACHE_EXPIRATION_TIME_PREF_NAME, this, true);
-      PlacesUtils.history.addObserver(this, true);
-      this._observersAdded = true;
-    }
-
-    this.cacheLifespan = this.prefs.getIntPref(CACHE_EXPIRATION_TIME_PREF_NAME);
-
-    this.maxpreviews = this.prefs.getIntPref(DISABLE_THRESHOLD_PREF_NAME);
-
-    // If the user toggled us on/off while the browser was already up
-    // (rather than this code running on startup because the pref was
-    // already set to true), we must initialize previews for open windows:
-    if (this.initialized) {
-      let browserWindows = Services.wm.getEnumerator("navigator:browser");
-      while (browserWindows.hasMoreElements()) {
-        let win = browserWindows.getNext();
-        if (!win.closed) {
-          this.onOpenWindow(win);
-        }
-      }
-    }
-  },
-
-  disable() {
-    while (this.windows.length) {
-      // We can't call onCloseWindow here because it'll bail if we're not
-      // enabled.
-      let tabWinObject = this.windows[0];
-      tabWinObject.destroy(); // This will remove us from the array.
-      delete tabWinObject.win.gTaskbarTabGroup; // Tidy up the window.
-    }
-  },
-
-  addPreview(preview) {
-    this.previews.push(preview);
-    this.checkPreviewCount();
-  },
-
-  removePreview(preview) {
-    let idx = this.previews.indexOf(preview);
-    this.previews.splice(idx, 1);
-    this.checkPreviewCount();
-  },
-
-  checkPreviewCount() {
-    if (!this._prefenabled) {
-      return;
-    }
-    this.enabled = this.previews.length <= this.maxpreviews;
-  },
-
-  onOpenWindow(win) {
-    // This occurs when the taskbar service is not available (xp, vista)
-    if (!this.available || !this._prefenabled)
-      return;
-
-    win.gTaskbarTabGroup = new TabWindow(win);
-  },
-
-  onCloseWindow(win) {
-    // This occurs when the taskbar service is not available (xp, vista)
-    if (!this.available || !this._prefenabled)
-      return;
-
-    win.gTaskbarTabGroup.destroy();
-    delete win.gTaskbarTabGroup;
-
-    if (this.windows.length == 0)
-      this.destroy();
-  },
-
-  resetCacheTimer() {
-    this.cacheTimer.cancel();
-    this.cacheTimer.init(this, 1000 * this.cacheLifespan, Ci.nsITimer.TYPE_ONE_SHOT);
-  },
-
-  // nsIObserver
-  observe(aSubject, aTopic, aData) {
-    if (aTopic == "nsPref:changed" && aData == TOGGLE_PREF_NAME) {
-      this._prefenabled = this.prefs.getBoolPref(TOGGLE_PREF_NAME);
-    }
-    if (!this._prefenabled) {
-      return;
-    }
-    switch (aTopic) {
-      case "nsPref:changed":
-        if (aData == CACHE_EXPIRATION_TIME_PREF_NAME)
-          break;
-
-        if (aData == DISABLE_THRESHOLD_PREF_NAME)
-          this.maxpreviews = this.prefs.getIntPref(DISABLE_THRESHOLD_PREF_NAME);
-        // Might need to enable/disable ourselves
-        this.checkPreviewCount();
-        break;
-      case "timer-callback":
-        this.previews.forEach(function(preview) {
-          let controller = preview.controller.wrappedJSObject;
-          controller.resetCanvasPreview();
-        });
-        break;
-    }
-  },
-
-  /* nsINavHistoryObserver implementation */
-  onBeginUpdateBatch() {},
-  onEndUpdateBatch() {},
-  onVisit() {},
-  onTitleChanged() {},
-  onFrecencyChanged() {},
-  onManyFrecenciesChanged() {},
-  onDeleteURI() {},
-  onClearHistory() {},
-  onDeleteVisits() {},
-  onPageChanged(uri, changedConst, newValue) {
-    if (this.enabled && changedConst == Ci.nsINavHistoryObserver.ATTRIBUTE_FAVICON) {
-      for (let win of this.windows) {
-        for (let [tab, ] of win.previews) {
-          if (tab.getAttribute("image") == newValue) {
-            win.onLinkIconAvailable(tab.linkedBrowser, newValue);
-          }
-        }
-      }
-    }
-  },
-
-  QueryInterface: XPCOMUtils.generateQI([
-    Ci.nsISupportsWeakReference,
-    Ci.nsINavHistoryObserver,
-    Ci.nsIObserver
-  ]),
-};
-
-XPCOMUtils.defineLazyGetter(AeroPeek, "cacheTimer", () =>
-  Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer)
-);
-
-XPCOMUtils.defineLazyServiceGetter(AeroPeek, "prefs",
-                                   "@mozilla.org/preferences-service;1",
-                                   "nsIPrefBranch");
-
-AeroPeek.initialize();